Civil Engineering Reference
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80
229
19.6
5
z
p
y
z
i
y
612.2
80
1 1 . 9
10
z
z
(a) 610 × 229 UB 125
I
y
= 98 610 cm
4
W
pl,y
= 3676 cm
3
(b) Tee-section
Figure 5.40
Worked examples 1, 2, and 18.
Solution
. Using the thin-walled assumption and equations 5.57 and 5.58,
z
i
=
(
80
+
5
/
2
)
×
10
×
(
80
+
5
/
2
)/
2
(
80
×
5
)
+
(
80
+
5
/
2
)
×
10
=
27.8 mm
I
y
=
(
80
×
5
)
×
27.8
2
+
(
82.5
3
×
10
/
12
)
+
(
82.5
×
10
)
×
(
82.5
/
2
−
27.8
)
2
mm
4
=
92.63 cm
4
W
el
,
y
=
92.63
/
{
(
8.25
−
2.78
)/
10
}=
16.93 cm
3
Alternatively, the equations of Figure 5.6 may be used.
5.12.3 Example3-properties of an angle section
Problem
. Determinetheproperties
A
,
I
y
1
,
I
z
1
,
I
y
1
z
1
,
I
y
,
I
z
,and
α
ofthethin-walled
angle section shown in Figure 5.41c.
Solution
. Using the thin-walled assumption, the angle section is replaced by two
rectangles 142.5
(
=
150
−
15
/
2
)
×
15 and 82.5
(
=
90
−
15
/
2
)
×
15, as shown in
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